FIG. 1 illustrates a prior art technique for analyzing data. A data source 100_1, such as a relational database, may have its data migrated to a persistent data store 104 through the use of an Extract, Transform and Load (ETL) module 102_1. As its name implies, an ETL module extracts data, transforms the data to a specified format and then loads it into the persistent data store. Additional data sources 100_2 through 100_N may be processed in a similar manner to augment the persistent data store 104. Thereafter, a query engine 106 may be used to apply ad hoc queries to the persistent data store 104.
Prior art systems of this type require data to be migrated and stored persistently prior to analysis. As the number of data sources proliferates there is a growing need to analyze data prior to migration and persistent storage.